The 1901 census in Canada includes a field for race - if you know of any descendants who would have been listed on that census you can check what race is listed. This isn't always fool proof - I have metis ancestors who were not listed as aboriginals.
Alternatively, in Canada in 1885 metis children (children of caucasion/aboriginal descent) were allowed to file land claims as part of a government act. If you know the name of an ancestor you can search the online database to see if they filed a claim:
There are also several books that have been published about metis families in Canada. I checked the Charles Denney papers at the Glenbow Archives, but there are no Bradley's listed - could the family be listed under another surname?